dpmiller

Down the big long lane...

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3 hours ago, Onoff said:

 

What model RCD is it out of interest?

 

It's an ESR, Clive anRCD2-80100T. Evidently built down to a price...

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@Declan52 It's a 270l tank,  there's piccies upthread a bit. It was quoted as a very high recovery coil and that seems to be the case alright   I'll get a photo of the unit installed later, but it's still a bit lashed-in for now, insulation to finish and the unit levelled etc.

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Just received the SAP and airtightness certification through. House comes out as A96, and the airtightness is as previous at 1.783m3/h/m2 which is 1.37ACH. Well chuffed with that!

 

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I hope the rotary isolator never gives trouble and nobody wants to take the cover off :ph34r:

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plenty of room actually Dave, the angle is deceiving (and I'm left-handed lol). It's 10+" off the wall.

 

 

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2 hours ago, dpmiller said:

 

It's an ESR, Clive anRCD2-80100T. Evidently built down to a price...

 

They do do an A type, part number RCD2/A-80100 "Type A 2-Pole RCD - 80A 100mA".

 

Would that be a better bet if you want to keep to the same make? 

 

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Don't care about the make tbh as it's in a single housing in the meter box. Good spot tho, either A or maybe F? I'll have a mooch around see what I can find.

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48 minutes ago, dpmiller said:

Don't care about the make tbh as it's in a single housing in the meter box. Good spot tho, either A or maybe F? I'll have a mooch around see what I can find.

 

I was going to suggest Type F but ESR don't appear to do one.

 

So you want a time delay, 100mA, Type F...

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How about a:

 

Doepke 80-2/0.10.DFS2.F

 

Type F, 80A, 100mA, 10ms delay etc

 

See page 11:

 

rcds.pdf

 

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Thanks Clive.

 

So I read the meter. About 4pm yesterday til 8pm today; ASHP, MVHR, and a dehumidifier, minus very little solar production equals 53kWh. And that has the slab up to 19c and the ground floor in general around 17c. That's a shedload more efficient than the willis!

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a few days in and the screed is pushing out a shedload of water again, MVHR has gone into humidity override. Consumption is about 40kWh/day, slab at 22c/ GF 19c/ unheated FF bedrooms 17c.

I'm currently running in series/buffer mode, so heatpump flow is going through the TS before heading to the UFH mixer, I've got the heating/buffer sensor strapped to the return pipe after the UFH and bypass, and the ASHP is controlling on that. Flow and TS are both 37c at a setpoint of 30c

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Do you just have UFH in the ground floor or first as well?

 

What thickness is your screed?

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the landing/balcony and the two bathrooms upstairs both have UFH. I've ran pipes for rads in the bedrooms but don't think I'll need any, I reckon the heat rising then banking in the screed will keep them about right.

 

  Screed is dead-on the 50mm upstairs but the GF is a bit thicker as the subfloor had a bit of variance and I had been erring on the side of caution cf. level access at the front door. 60-75mm...

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So all you have is the flow and return to your thermal store, mains power from the switch on the outside wall and the 2 other cables. What are they for???

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the unit has an rj12 cable to go to the controller, plus two sensors- one for the hot tank and one for the buffer/ heating. You can run it like this using it's controller for time and DHW/flow temperature control, it needs nothing more. but...

There are dry contact inputs for heat/ DHW/ cooling, and available outputs for aux pump, motor valves, immersion backup. I just pulled in a mains-rated multicore and a screened Cat5 to cover all eventualities; for now that's a pair of the cat5 to extend the sensor up to the tank, and in future two switch wires for heat demand and cooling.

 

One thing I've noticed is that it's quite flow-sensitive.  While the flowswitch will let the unit run quite happily at modest flow rates (flowsetter is stuck in Hermes somewhere, boo) the system will throttle the output to keep the flow delta under 10c. Raise the flow, and the power increases too...

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So, this heat pump thingy...

One of the advantages of getting all the kit up and running is being able to monitor and if necessary reconsider things. And so after a couple of weeks running we came to the conclusion that the two bigger upstairs bedrooms- both North facing-  did need radiators after all. Pipes were already laid in so a quick trip to Screwys for a pair of 600x1200 double convectors and... done. I raised the flow temperature from the ASHP to get meaningful heat and paradoxically this has improved economy.

I'll probably need to explain that bit.

So I'm trying to be all things to all men without using any fancy control strategies. Flow from the heatpump passes through the TS at all times. But when there are no demands the TS coil is gated/bypassed, to stem any convective losses. Return from the TS is available to both the UFH and rad manifolds. If neither of them demand, an autobypass ensures there's still flow. All the pumps stats and zone valves are on a separate RCBO to the ASHP so that in emergency/power outage the heating system can run off the TS- heated by the boiler stove.

 

The ASHP controls on DHW tank temp, and also on buffer/ return temp. It has programmable hysteresis and overshoot for each. The upside of this and fitting the rads? Flow from the ASHP is naturally higher than return so more energy into the bottom of the TS. The ASHP setpoint is 32c (return) but the flow could be up to about 40c to get it there. Hence the TS now has enough energy in it to impart heat to the house. Nice. And the extra heat in the two upstairs beds means no cool air falling into the hall. Even nicer.

TLDR:  That extra energy means that the TS actually buffers, so the HP is running less and longer.

 

Whole house is at an indicated 19c but the slab heat makes it feel much warmer. Almost too warm already...  and that's at a consistent 10kWh/overcast day and cool night.

Clear sun is already getting the top of the tank up to 75-85c on the diverter and on days like the the ASHP consumption is down at around 5kWh.

 

 

And I've finally got the monitoring software set up for the PV. Yay! Took a while but we got there...

 

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so the East-West panel split seems to be working well. With apologies for the dip around noon, I've been having problems getting the DTU to receive from all the inverters happily. But I think I've found the sweet spot now...

 

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What's your panel setup? I'm going for 50% south, 25% east and 25% west.

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6 are SE, 6 SW, and one of those is shaded by a chimney which is the dip at 3pm. Plus sticky-out gables get in the way a bit too. But still, it's production the whole way from sunrise to sunset.

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On 31/03/2021 at 10:17, dpmiller said:

So, this heat pump thingy...

One of the advantages of getting all the kit up and running is being able to monitor and if necessary reconsider things. And so after a couple of weeks running we came to the conclusion that the two bigger upstairs bedrooms- both North facing-  did need radiators after all. Pipes were already laid in so a quick trip to Screwys for a pair of 600x1200 double convectors and... done. I raised the flow temperature from the ASHP to get meaningful heat and paradoxically this has improved economy.

I'll probably need to explain that bit.

So I'm trying to be all things to all men without using any fancy control strategies. Flow from the heatpump passes through the TS at all times. But when there are no demands the TS coil is gated/bypassed, to stem any convective losses. Return from the TS is available to both the UFH and rad manifolds. If neither of them demand, an autobypass ensures there's still flow. All the pumps stats and zone valves are on a separate RCBO to the ASHP so that in emergency/power outage the heating system can run off the TS- heated by the boiler stove.

 

The ASHP controls on DHW tank temp, and also on buffer/ return temp. It has programmable hysteresis and overshoot for each. The upside of this and fitting the rads? Flow from the ASHP is naturally higher than return so more energy into the bottom of the TS. The ASHP setpoint is 32c (return) but the flow could be up to about 40c to get it there. Hence the TS now has enough energy in it to impart heat to the house. Nice. And the extra heat in the two upstairs beds means no cool air falling into the hall. Even nicer.

TLDR:  That extra energy means that the TS actually buffers, so the HP is running less and longer.

 

Whole house is at an indicated 19c but the slab heat makes it feel much warmer. Almost too warm already...  and that's at a consistent 10kWh/overcast day and cool night.

Clear sun is already getting the top of the tank up to 75-85c on the diverter and on days like the the ASHP consumption is down at around 5kWh.

 

 

How are you finding the usability and reliability of the coolenergy unit? Good point about the rads, think I'll do the same. Are they on a supply each from the.manifold or shared? 

 

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Each rad is one loop on the manifold @Conor So far I'm finding the unit itself very hard to fault. Some of the terms used in the settings are a bit obscure, but no worse than some of the language the likes of Samsung use in their menus. The App works pretty well too, although I know it's really still in beta.

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Thanks David. I think I'll do the same then. Did you put rads in all of the rooms? We'll have four bedrooms and two bathrooms.

 

Have you investigated a cooling setup yet? Something I'm keen to have the option of, even though it'll be rarely used.

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I've currently only put rads in the two larger north-facing rooms as they're the two we'll be using. The two smaller rooms get the sun first thing and aren't affected so badly. But there'll be a towel rail in each bathroom. (but yes, there are pipes led into the other two rooms just in case)

 

Cooling is easy, you just need to manually change operating mode on the controller- you can have a single mode heat/cool/dhw or your choice of two. Not difficult or hidden. It has the same kind of  time&temp or weather compensating setpoints for cooling as for heating.

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So in the summer you can have it set to DHW in the morning and cooling in the afternoon easily enough? 

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Yes, it will switch between heating/DHW modes as you require in the winter, and cooling/DHW in the summer with a couple of keypresses. DHW has priority as is normal, and it's up to you to work out how to give it heating and cooling demands from your stats.

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